Compound bow

ABSTRACT

A compound bow includes a bow main body including a handle and a pair of limbs. Upper and lower pulleys are coupled to the rear end of each limb. A bowstring is provided and a cam that is coupled to each pulley. A rotating wheel is coupled with the rotating shaft of the pulley. Cam cables are wound around the cams, in which one end of each cam cable is coupled to one pulley and the other end thereof is coupled to the other pulley. A cam cable guide member has one end rotatably coupled to the rotating shaft of the pulley, and at the other end of which a support member for supporting the cam cable is formed in order to make a portion of the cam cable extended from the rotating wheel guided in parallel with the pulley.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2013-0100228, filed on Aug. 23, 2013 and No. 10-2013-0164958, filedon Dec. 27, 2013 in the Korean Intellectual Property Office, thedisclosures of which are incorporated in their entireties herein byreference and to which priority is claimed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a compound bow, and more particularly,to a compound bow which can prevent distortion of the bow and improveaccuracy of an arrow when a bowstring is pulled.

2. Description of the Related Art

Typically, compound bows are configured so that a bowstring may beeasily pulled without using a large force and arrow shooting power isincreased during shooting, by using an effect of a cam or wheel, to thusresult in a fast speed of an arrow and have very strong power, and arewidely used mainly for hunting.

As shown in FIGS. 1 to 3, a conventional compound bow is configured tohave upper limbs 20 that are coupled to the upper portion of a handle 10at the center of which a grip portion is formed, and lower limbs 26coupled to the lower portion of the handle 10. A cut-out portion 21 isformed between the upper limbs 20 whose edges 22 are spaced apart fromeach other, and a cut-out portion 27 is formed between the lower limbs26 whose edges 28 are spaced apart from each other. Rotating shafts 70are horizontally formed through the edges 22 of the upper limbs 20 andthe cut-out portion 21, and through the edges 28 of the lower limbs 26and the cut-out portion 27, respectively. Upper and lower pulleys 30 and36 are rotatably combined with the respective rotating shafts 70.

A bowstring 50 is wound along a guide groove 31 or 37 of each pulley 30or 36, and the respective ends of the bowstring 50 are combined witheach pulley 30 or 36. In addition, a cam 32 or 38 rotating with thepulley 30 or 36 is coupled in each pulley 30 or 36. As the bowstring 50is pulled, cam cables 40 and 46 are formed so as to be wound on the cams32 and 38, respectively. One end of each cam cable 40 or 46 is coupledto a pulley 30 or 36 to which each cam 32 or 38 is coupled, and theother end of each cam cable 40 or 46 is coupled to each rotating shaft70 at both sides of the cut-out portion 21 or 27 of each of the opposinglimbs 20 and 26 in the form of Y-shaped buss cables 40 a and 46 a.

Further, a cable guard 60 is laterally mounted at one side of a centerportion of a handle 10, in which the cable guard 60 pushes the camcables 40 and 46 to one side of the bowstring 50 so that an arrow is notprevented from being shot during shooting. In addition, a slide 66 ismovably mounted on the cable guard 60 in which the cam cables 40 and 46are inserted into the slide 66.

When the bowstring 50 is pulled in the prior art compound bow that isconfigured as described above, the lower and upper pulleys 30 and 36 arerotated and thus the cams 32 and 38 coupled to the lower and upperpulleys 30 and 36 are rotated, to thereby wind and pull the cam cables40 and 46. When the bowstring 50 is released in a let-off state, anarrow obtains a strong driving force by a strong elastic force of thebow which returns to an original position instantaneously.

However, in order to prevent the cam cables 40 and 46 which are locatedin front of the bowstring 50 from interfering with the shooting of anarrow in the compound bow, the cam cables 40 and 46 are compulsivelysupported in one direction by the cable guard 60 and the cams 32 and 38are combined on an identical one side surface of the respective pulleys30 and 36. Therefore, the pulleys 30 and 36 around which the bowstring50 is wound are not located at the center of each of the limbs 20 and 26as shown in FIG. 2. Accordingly, when the bowstring 50 is pulled, thebow limbs 20 and 26 and pulleys 30 and 36 are twisted as shown in FIG.3. As a result, the inherent strength of the bow is not exhibited andthe accuracy of the arrows is also dropped. Thus, although the busscables 40 a and 46 a are adjusted with a tool to thereby control the bowlimbs to be inclined to the left and right, it is very difficult toadjust the buss cables 40 a and 46 a for the left and right balance ofthe bow limbs 20 and 26 except for a person who has a skill ofadjustment of the buss cables 40 a and 46 a, due to difference of theforces applied on the limbs when compared with an initial state of thelimbs when the bowstring 50 is pulled.

SUMMARY OF THE INVENTION

To solve the above conventional problems or defects, it is an object ofthe present invention to provide a compound bow to prevent twisting ofthe bow, to exhibit inherent strength of the bow, and to improveaccuracy of an arrow.

To accomplish the above and other objects of the present invention,according to an aspect of the present invention, there is provided acompound bow comprising: a bow main body including a handle at a centralportion of which a grip portion is formed and a pair of limbs that arerespectively coupled to both ends of the handle; upper and lower pulleyassemblies each including a pulley that is rotatably coupled to arotating shaft formed on the rear end of each limb, and a cam that iscoupled to one side of the pulley and rotating with the pulley; abowstring whose either end is wound and coupled to the pulley of each ofthe upper and lower pulley assemblies; and two cam cables that are woundaround the cam of each of the upper and lower pulley assemblies as thebowstring is pulled, in which one end of each of the two cam cables iscoupled to one of the upper and lower pulley assemblies, and the otherend thereof is coupled to the other of the upper and lower pulleyassemblies or the rotating shaft of the other of the upper and lowerpulley assemblies; wherein at least one of the upper and lower pulleyassemblies further comprises: a rotating wheel that is coupled with therotating shaft of the pulley on the other side surface opposing to oneside surface of the pulley to which the cam is coupled, in which one ofthe two cam cables is coupled to the other side surface of the pulley,wound on the rotating wheel, and extended toward the other of the upperand lower pulley assemblies; and a cam cable guide member one end ofwhich is rotatably coupled to the rotating shaft of the pulleyseparately from the pulley, at one side of the rotating wheel, in whichthe cam cable guide member is extended by a predetermined length alongone of the cam cables extended toward the other of the upper and lowerpulley assemblies from the rotating wheel, and at the other end of whicha support member for supporting one of the cam cables is formed in orderto make a portion of one of the cam cables extended from the rotatingwheel guided in parallel with the pulley.

Preferably but not necessarily, the rotating wheel is rotatably coupledto the rotating shaft separately from the pulley.

Preferably but not necessarily, the support member of the cam cableguide member comprises a guide pulley and a support pulley that arerespectively rotatably coupled to two shaft members respectively locatedat both sides of the cam cable, in which the cam cable is supportedbetween the guide pulley and the support pulley.

Preferably but not necessarily, a guide groove for guiding the cam cableis formed on an outer circumferential surface of the guide pulley.

Preferably but not necessarily, the support pulley is formed at thefront of the guide pulley, and is located at a longer distance from therotating shaft of the cam cable guide member than the guide pulley.

Preferably but not necessarily, the support pulley is formed to have anouter diameter of an outer circumferential surface of the support pulleythat guides the cam cable in contact with the cam cable becomes smallerinwards, and thereby guide the cam cable to a cable guard that iscoupled to the handle of the bow main body and pushes the cam cable inone direction.

Preferably but not necessarily, the compound bow further comprises asupport bar one end of which is rotatably coupled to the rotating shaftseparately from the pulley at the other side surface of the pulley towhich the cam cable guide member is coupled, so as to oppose the camcable guide member, and at the other end of which two supportprotrusions are formed for supporting each of the guide pulley and thepulley support of the cam cable guide member.

Preferably but not necessarily, two coupling portions to which therotating shaft is coupled are formed at one end of the cam cable guidemember, in which the two coupling portions are coupled to the rotatingshaft at both sides of one of two branches adjacent to the rotatingwheel of the two branches that form a rear portion of the limbs, and thecam cable guide member is made in an arch-shaped form.

Advantageous Effects

As described above, the present invention provides a compound bow toprevent twisting of the bow during use, to exhibit inherent strength ofthe bow, and to improve synchronizing to thus improve accuracy of anarrow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a conventional compound bow.

FIG. 2 is a rear view of the compound bow of FIG. 1.

FIG. 3 is a perspective view showing a twisted state of a pulleyassembly coupled to a limb of FIG. 1.

FIG. 4 is a side view showing a compound bow according to a firstembodiment of the present invention before a bowstring is pulled.

FIG. 5 is a detailed view of a pulley assembly that is coupled to one oflimbs in FIG. 4.

FIG. 6 is a side view showing a compound bow according to the firstembodiment of the present invention after a bowstring has been pulled.

FIG. 7 is a detailed view of a pulley assembly that is coupled to one oflimbs in FIG. 6.

FIG. 8 is a side view of the pulley assembly of FIG. 7 seen from thefront side of the compound bow.

FIG. 9 is a side view showing a compound bow according to a secondembodiment of the present invention before a bowstring is pulled.

FIG. 10 is a detailed view of a pulley assembly that is coupled to oneof limbs in FIG. 9.

FIG. 11 is a side view showing a compound bow according to the secondembodiment of the present invention after a bowstring has been pulled.

FIG. 12 is a detailed view of a pulley assembly in FIG. 11.

FIG. 13 is a side view of the pulley assembly of FIG. 12 seen from therear side of the compound bow.

DETAILED DESCRIPTION OF THE INVENTION

The above and/or other objects and/or advantages of the presentinvention will become more apparent by the following description ofembodiments of the present invention.

Hereinbelow, a compound bow according to a first embodiment of thepresent invention will be described in more detail with reference to theaccompanying drawings.

FIG. 4 is a side view showing a compound bow according to a firstembodiment of the present invention before a bowstring is pulled. FIG. 5is a detailed view of a pulley assembly that is coupled to one of limbsin FIG. 4. FIG. 6 is a side view showing a compound bow according to thefirst embodiment of the present invention after a bowstring has beenpulled. FIG. 7 is a detailed view of a pulley assembly that is coupledto one of limbs in FIG. 6. FIG. 8 is a front view of the pulley assemblyof FIG. 7 seen from the front side of the compound bow.

Referring to FIGS. 4 to 8, a compound bow according to a firstembodiment of the present invention includes: a bow main body 100including a handle 102 at a central portion of which a grip portion isformed and a pair of limbs 103 that are respectively coupled to bothends of the handle 102; upper and lower pulley assemblies each includinga pulley 110 that is rotatably coupled to a rotating shaft 101 formed onthe rear end of each limb 103, and a cam 200 that is coupled to one sideof the pulley 110 and rotating with the pulley 110; a bowstring 140whose either end is wound and coupled to the pulley 110 of each of theupper and lower pulley assemblies; and two cam cables 150 that are woundaround the cam 200 of each of the upper and lower pulley assemblies asthe bowstring 140 is pulled, in which one end of each of the two camcables 150 is coupled to one of the upper and lower pulley assemblies,and the other end thereof is coupled to the other of the upper and lowerpulley assemblies or the rotating shaft 100 of the other of the upperand lower pulley assemblies.

At least one of the upper and lower pulley assemblies further includes:a rotating wheel 120 that is rotatably coupled with the rotating shaft101 of the pulley 110 on the other side surface opposing to one sidesurface of the pulley 110 to which the cam 200 is coupled, in which oneof the two cam cables 150 is coupled to the other side surface of thepulley 110, wound on the rotating wheel 120, and extended toward theother of the upper and lower pulley assemblies; and a cam cable guidemember 300 one end of which is rotatably coupled to the rotating shaft120 of the pulley 110 separately from the pulley 110, at one side of therotating wheel 120, in which the cam cable guide member 300 is extendedby a predetermined length along one of the cam cables 150 extendedtoward the other of the upper and lower pulley assemblies from therotating wheel 120, and at the other end of which a support member 310for supporting one of the cam cables 150 is formed in order to make aportion of one of the cam cables 150 extended from the rotating wheel120 guided in parallel with the pulley 110.

As shown in FIGS. 4 to 8, the compound bow according to a firstembodiment of the present invention employs a dual cam system therespective components of which will be described below in more detail.First, the bow main body 100 includes a handle 102 at a central portionof which a grip portion is formed so as to be gripped by a user, and apair of limbs 103 each having two branches. A rotating shaft 101 isformed at the rear end of each limb 103, in which a pulley assembly isrotatably coupled on the rotating shaft 101 between the two branches ofeach limb 103. A cable guard 105 that pushes the cam cables 150 to oneside of the bowstring 140 is coupled at the central portion of thehandle 102, in order to prevent an arrow from being interrupted duringshooting.

Then, each of the upper and lower pulley assemblies is rotatably coupledto the rotating shaft 101 at the rear end of each limb 103, andincludes: a pulley 110 that is rotatably coupled to the rotating shaft101 formed at the rear end of each limb 103; and a cam 200 coupled toone side of the pulley 110 and rotating with the pulley 110.

Each pulley 110 is formed of an oval-like plate-shaped member, and hasan eccentric through-hole that is formed at the center of the pulley 110and through which the rotating shaft 101 is coupled. Further, a guidegroove that is depressed down to a predetermined depth is formed on theouter circumferential surface of each pulley 110 so that the bowstring140 may be wound on the outer circumferential surface of each pulley110. A fixing protrusion 111 for fixing one end of the bowstring 140wound on the guide groove is formed at one side of each pulley 110. Inaddition, fixing protrusions 112 and 113 are formed in each pulley 110in which the cam cables 150 are fixed to the fixing protrusions 112 and113.

The cam 200 is coupled to one side of each pulley 110 and is rotatedwith rotation of the pulley 110 to thus make the cam cables 150 wound onthe cam 200, and includes: a cam cable winding portion 210 fabricated inan arc-shaped form and on which one of the cam cables 150 is wound; anda cam module 220 that has a pivot axis 221 at a position spaced by apredetermined distance from the rotating shaft 101 of the pulley 110 towhich the cam 200 is coupled, and that is rotatably coupled to the pivotaxis 221 by a predetermined angle from the cam cable winding portion210, in which a cam cable winding groove is formed on the outercircumferential surface of the cam module 220, and the cam cable 150 iswound around the cam cable winding portion 210 and then sequentiallywound on the outer circumferential surface of the cam module 220 whenthe bowstring 140 is pulled.

The cam cable winding portion 210 is arc-shaped so that the cam cable150 is wound on the cam cable winding portion 210, when the bowstring140 is pulled, in which one end of the cam cable 150 is coupled to thefixing protrusion 112 that is located in the vicinity of the cam cablewinding portion 210. In addition, a cam cable winding groove is formedon the outer circumferential surface of the cam cable winding portion210 so that the cam cable 150 is wound on the outer circumferentialsurface of the cam cable winding portion 210.

The cam module 220 has the pivot axis 221 at a position spaced by apredetermined distance from the rotating shaft 101 of the pulley 110 towhich the cam 200 is coupled, and is rotatably coupled to the pivot axis221 by a predetermined angle from the cam cable winding portion 210, andis configured to have a gentle slope portion 222 formed of a gentlearc-shaped curve and a steep slope portion 223 that is extended from thegentle slope portion 222 to be close to the rotating shaft 101, to thusform a steep slope. Further, the cam cable winding grooves on which thecam cable 150 is wound are formed on the outer circumferential surfacesof the gentle slope portion 222 and the steep slope portion 223.Accordingly, the cam module 220 is rotated along with the pulley 110when the bowstring 140 is pulled, and thus the cam cable 150 issequentially wound on the gentle slope portion 222 and the steep slopeportion 223 of the cam module 220 adjacent to the cam cable windingportion 210. Thus, the cam module 220 is rotated by a predeterminedangle around the pivot axis 221 and is fixed to the pulley 110 by usinga bolt at a position where the cam module 220 has been rotated. Rotationof the module cam 220 is to adjust the length of the pull at a let-offstate.

The bowstring 140 is wound in the guide groove of the pulley 110 of eachpulley assembly and thus both ends of the bowstring 140 are coupled tothe fixing protrusions 111 formed on the respective pulleys 110.

The cam cables 150 are formed between a pair of the limbs 103 of the bowmain body 100 and are wound on the cams 200 formed in the respectivepulleys 110, as the bowstring 140 is pulled. One end of each of the camcables 150 is coupled to the fixing protrusion 113 formed on the pulley110 of one of the pulley assemblies, and then is wound around therotating wheel 120 that is rotatably coupled to the rotating shaft 101,and the other end of each of the cam cables 150 is extended toward theother of the pulley assemblies to then be fixed to the fixing protrusion112 of the pulley 110 of the other of the pulley assemblies. Therefore,as the bowstring 140 is pulled, the cam cables 150 are wound on the cam200 that is coupled to the other pulley 110 of the pulley assemblies.

The rotating wheel 120 is configured to have a through-hole at thecenter of the rotating wheel 120 in which the rotating shaft 101 of thepulley 110 is coupled into the through-hole, and to be coupled to therotating shaft 101 of the pulley 110 at the other side surface of thepulley 110, that is, at the other side surface opposing one side surfaceof the pulley 110 to which the cam 200 is coupled, and to be rotatablycoupled to the rotating shaft 101 of the pulley 110 separately from thepulley 110. Further, the cam cable winding groove into which the camcable is wound is formed on the outer circumferential surface of thecircular rotating wheel 120. Thus, the cam cable 150 is wound on therotating wheel 120 and then one end of the cam cable 150 is coupled tothe fixing protrusion 113 formed on the pulley 110 in the vicinity ofthe rotating wheel 120. The cam cable 150 is wound on the cam 200 of theother pulley 110 by the pulling of the bowstring 140, and accordingly aportion of the cam cable 150 wound on the rotating wheel 120 is releasedfrom the rotating wheel 120. Here, since the rotating wheel 120 isrotatably coupled to the rotating shaft 101 separately from the pulley110, friction between the cam cable 150 and the rotating wheel 120 isreduced to thus reduce the pulling force of the bowstring 140.

The cam cable guide member 300 plays a role of making a portion of thecam cable 150 extended from the rotating wheel 120 guided in parallelwith the pulley 110, and is rotatably coupled to the rotating shaft 101of the pulley 110 at one side surface of the rotating wheel 120 to thusbe extended by a predetermined length along the extending direction ofthe cam cable 150. To this end, a through-hole is formed at one end ofthe cam cable guide member 300 in which the rotating shaft 101 of thepulley 110 is coupled into the through-hole, and a support member 310for supporting the cam cable 150 is formed at the other end of the camcable guide member 300, in which a portion of the cam cable 150 extendedfrom the rotating wheel 120 is guided in parallel with the pulley 110.

The support member 310 of the cam cable guide member 300 includes aguide pulley 320 and a support pulley 330 that are respectivelyrotatably coupled to two shaft members 302 and 303 respectively locatedat both sides of the cam cable 150, in which the cam cable 150 issupported between the guide pulley 320 and the support pulley 330. Theguide pulley 320 plays a role of guiding the cam cable 150 to be guidedin parallel with the pulley 110, and is rotatably coupled to the shaftmember 302 that is protruded toward the pulley 110 at the other end ofthe cam cable guide member 300, in which a guide groove 311 for guidingthe cam cable 150 is formed on the outer circumferential surface of theguide pulley 320. The guide pulley 320 is formed closer to the rotatingshaft 101 than the support pulley 330.

The support pulley 330 plays a role of guiding the cam cable 150 to beguided in parallel with the pulley 110, together with the guide pulley320, and simultaneously guiding the cam cable 150 to be guided towardthe cable guard 105 via the support pulley 330. The support pulley 330is formed farther from the rotating shaft 101 at the front of the guidepulley 320 than the guide pulley 320, and is rotatably coupled to theshaft member 303 that is protruded toward the pulley 110 at the otherend of the cam cable guide member 300. The shaft member 303 to which thesupport pulley 330 is coupled is longer than the shaft member 302 towhich the guide pulley 320 is coupled. Thus, the support pulley 330 isalso larger than the guide pulley 320 in width. As shown in FIG. 8, thecam cable 150 is vertically from the rotating wheel 120 to the guidepulley 320, that is, in parallel with the pulley 110, and then is benttoward the other side surface of the pulley 110 over the guide pulley320 in order to be inserted into the cable guard 105. As describedabove, the cam cable 150 is bent toward the cable guard 105 over theguide pulley 320.

Further, as shown in FIG. 8, the support pulley 330 is configured tohave an outer circumferential surface that guides the cam cable 150 incontact with the cam cable 150 along the travelling direction of the camcable 150 in which the outer diameter of the outer circumferentialsurface becomes smaller inwards (that is, toward the pulley 110). Asshown in FIGS. 4 and 5, the cam cables 150 are formed askew from thepoint of view of the bow, and as shown in FIG. 8, the cam cable 150 isbent toward the other side surface of the pulley 110 over the guidepulley 320 in order to be inserted into the cable guard 105. Asdescribed above, since the support pulley 330 is configured so that theouter diameter of the outer circumferential surface of the supportpulley 330 that contacts the cam cable 150 becomes smaller inwards, thesupport pulley 330 supports the cam cable 150 from the incoming portionof the cam cable 150 to the outgoing portion of the cam cable 150 in thesupport pulley 330, and thus when the bowstring 140 is pulled, the camcable 150 is guided toward the cable guard 105 more reliably.

Since the cam cable guide member 300 is configured to have theabove-described structure, the cam cable 150 does not come into contactwith the pulley 110 and the cam cable 150 is also guided in parallelwith the pulley 110 when the bowstring 140 is pulled. As a result,direction of a force applied to each of the cam cables 150 is parallelto the bowstring 140, thereby preventing distortion of the bow limbs103.

Further, since the guide pulley 320 and the support pulley 330 thatguide the cam cable 150 are rotatably coupled to the shaft members 302and 303, respectively, the friction of the cam cable 150 in contact withthe guide pulley 320 and the support pulley 330 may be minimized to thusreduce a force that is needed to pull the bowstring 140.

Further, as shown in FIG. 8, a support bar member 400 is formed at theother side of the pulley 110 opposing one side of the pulley 110 towhich the cam cable guide member 300 is coupled, so as to oppose the camcable guide member 300. One end of the support bar member 400 isrotatably coupled to the rotating shaft 101 separately from the pulley110, and is extended to have the same length as the cam cable guidemember 300. Two support protrusions 402 and 403 that are protrudedtoward the support member 310 to support the guide pulley 320 and thesupport pulley 330 of the support member 310 are formed at the other endof the support bar member 400.

Thus, since the support bar member 400 opposite to the cam cable guidemember 300 is coupled to the rotating shaft 101 at the other side of thepulley 110 to which the cam cable guide member 300 is coupled, thepulley 110 that is rotated as the bowstring 140 is pulled may be locatedat the center of the limbs 103, thereby preventing distortion of thelimbs 103. Further, as shown in FIG. 8, the cam cable 150 is bent towardthe cable guard 105, and thus the guide pulley 320 and the supportpulley 330 that guide the cam cable 150 become tense by a force appliedinwards as the bowstring 140 is pulled. Accordingly, since the supportprotrusions 402 and 403 of the support bar member 400 are configured tosupport the guide pulley 320 and the support pulley 330 at the otherside of the guide pulley 320 and the support pulley 330, it is possibleto promote the structural stability.

The operation of the compound bow according to the first embodiment ofthis invention will be described below.

As shown in FIGS. 4 and 5, before the bowstring 140 is pulled, one endof the cam cable 150 is coupled to the fixing protrusion 113 of onepulley 110, and is wound around the rotating wheel 120, and the otherend of the cam cable 150 is coupled to the fixing protrusion 112 of theother pulley 110 over the guide pulley 320 and the support pulley 330 ofthe cam cable guide member 300. When the bowstring 140 is then pulled,the pulley 110 is rotated and thus the cam cable 150 wound around therotating wheel 120 is released from the rotating wheel 120 and thenwound on the cam 200 coupled to the opposing pulley 110. In addition,when the cam cable 150 is wound on the steep slope portion 223 of thecam module 220 coupled to the opposing pulley 110, the compound bowbecomes a let-off state at which an arrow may be shot as shown in FIGS.6 and 7.

Since the pulley 110 is located between the cam 200 and the rotatingwheel 120 in the compound bow according to the first embodiment of thepresent invention, and thus the pulley 110 is located at the center ofthe limbs 103, the conventional Y-shaped buss cables 40 a and 46 a shownin FIG. 1 are not required, and accordingly adjustment of the busscables 40 a and 46 a for preventing the bow limbs 103 from tilting fromside to side is also unnecessary. In addition, the cam cable 150 ispulled from the cam 200 and the rotating wheel 120 that are located onboth sides of the pulley 110 and thus balancing of the limbs 103 isimproved, to thereby provide an advantage capable of exerting thestrength of the original bow.

Further, when the cam cable 150 is released from the rotating wheel 120and is traveled to the cam 200 coupled to the pulley 110 of the opposingpulley assembly, as shown in FIG. 8, the cam cable 150 is guided by theguide pulley 320 and the support pulley 330 of the cam cable guidemember 300 coupled to the rotating shaft 101 at one side surface of therotating wheel 120, and the cam cable 150 is guided in parallel with thepulley 110 as the bowstring 140 is pulled, without contact with thepulley 110 due to the guide pulley 320 and the support pulley 330. As aresult, direction of the force being applied to the cam cable 150 isparallel to the bowstring 140, to thereby enhance the left and rightbalancing of the limbs, and improve synchronizing where both cams 200become a let-off state simultaneously, and to thus also provide aneffect of improving accuracy of an arrow.

Further, a portion of the cam cable 150 wound on the rotating wheel 120by pulling of the bowstring 140 is released from the rotating wheel 120.Here, since the rotating wheel 120 is rotatably coupled to the rotatingshaft 101 separately from the pulley 110, friction between the cam cable150 and the rotating wheel 120 is reduced to thus reduce the forceneeded to pull the bowstring 140.

Meanwhile, the example applied to the compound bow of the dual camsystem has been described as the embodiment of the present invention,but an example applied to a compound bow of one & a half (1&½) camsystem may be employed as another embodiment of the present invention.Although not shown, in the case that the present invention is applied toa compound bow of 1&½ cam system, a pulley assembly that is coupledbetween the respective limbs 103 will be described below. A lower pulleyassembly that is coupled between the respective lower limbs 103 is thesame as the pulley assembly of the embodiment shown in FIGS. 4 and 6.That is, the lower pulley assembly includes: the pulley 110; the cam 200which is coupled to one side of the pulley 110; the rotating wheel 120which is coupled to the other side of the pulley 110; and the cam cableguide member 300.

However, the upper pulley assembly includes: the pulley 110; and the cam200 which is coupled to the pulley 110. Accordingly, one end of one ofthe cam cables 150 is coupled to the rotating shaft of the upper pulleyassembly in a buss cable form, and the other end thereof is coupled toone side surface of the lower pulley 110 so as to be wound on the cam200 of the lower pulley assembly. In addition, one end of the other ofthe cam cables 150 is coupled to one side surface of the pulley 110 ofthe upper pulley assembly so as to be wound on the cam 200 of the upperpulley assembly, and the other end thereof is wound on the rotatingwheel 120 of the lower pulley assembly and coupled to the other sidesurface of the pulley 110. Both ends of the bowstring 150 are wound onand coupled to the respective pulleys.

As described above, even in the case that the present invention isapplied to the compound bow of the 1&½ cam system, a configuration ofthe lower pulley assembly is the same as the previous embodiment, andmay have the same effect as the lower pulley assembly.

Next, a compound bow according to a second embodiment of the presentinvention will be described with reference to the drawings. FIG. 9 is aside view showing a compound bow according to a second embodiment of thepresent invention before a bowstring is pulled.

FIG. 10 is a detailed view of a pulley assembly that is coupled to oneof limbs in FIG. 9. FIG. 11 is a side view showing a compound bowaccording to the second embodiment of the present invention after abowstring has been pulled. FIG. 12 is a detailed view of a pulleyassembly in FIG. 11. FIG. 13 is a side view of the pulley assembly ofFIG. 12 seen from the rear side of the compound bow.

The description of the compound bow according to the second embodimentof the present invention focuses on a different configuration from thedescription of the first embodiment of the present invention. In thecompound bow according to the second embodiment of the presentinvention, the cam 200 is coupled to one side of each pulley 110 and isrotated with rotation of the pulley 110 to thus make the cam cables 150a and 150 b wound on the cam 200, and includes: a cam cable windingportion 210 fabricated in an arc-shaped form and on which the cam cables150 a and 150 b are wound; and a cam module 220 that is rotatablycoupled to the pulley 110 by a predetermined angle from the cam cablewinding portion 210, around a pivot point “A” at a position spaced by apredetermined distance from the rotating shaft 101 of the pulley 110 towhich the cam 200 is coupled, in which a cam cable winding groove isformed on the outer circumferential surface of the cam module 220, andthe cam cables 150 a and 150 b are wound around the cam cable windingportion 210 and then sequentially wound on the outer circumferentialsurface of the cam module 220 when the bowstring 140 is pulled.

In addition, the cam 200 further includes a fixing unit that makes thecam module 220 rotated by a predetermined angle around the pivot point“A” in order to control the draw length of the let-off state of thecompound bow, and that makes the cam module 220 fixed to the pulley 110at a position where the cam module 220 has been rotated.

The fixing unit makes the cam module 220 rotated by a predeterminedangle around the pivot point “A,” and makes the cam module 220 fixed tothe pulley 110 at a position where the cam module 220 has been rotated.To this end, an arc-shaped positioning hole 230 centered at the pivotpoint “A” is formed in the cam module 220, and a coupling hole (notshown) is formed in the pulley 110 to which the cam module 220 iscoupled. Thus, when the cam module 220 is rotated by a predeterminedangle around the pivot point “A,” and a coupling member 115 is coupledto the coupling hole (not shown) formed in the pulley 110 at apredetermined position of the positioning hole 230, the cam module 220is coupled to the pulley 110. In the present invention, when a bolt asthe coupling member 115 is inserted into the positioning hole 230 and isscrew-coupled into the coupling hole (not shown) formed in the pulley110, the cam module 220 is coupled to the pulley 110. In addition, anarc-shaped coupling hole 116 centered at the pivot point “A” likewise isformed in the pulley 110 as an additional fixing unit, and a bolt 117 iscoupled to a bolt hole formed at a predetermined position in the cammodule 220. When the bolt 117 passes through the arc-shaped couplinghole 116 formed in the pulley 110 and a nut is coupled to one end of thebolt 117, the cam module 220 is additionally secured to the pulley 110.

The cam module 220 having such a structure can adjust the draw length ofthe bowstring 140. Thus, when the cam module 220 of the upper and lowerpulley assemblies 107 and 108 are identically rotated by an identicalangle from the cam cable winding portion 210 around the pivot point “A”and the cam module 220 is again secured to the pulley 110 at a positionwhere the cam module 220 has been rotated, the length of the cam cables150 a and 150 b that are wound on the gentle slope portion 222 of thecam module 220 increases in comparison with the previous state. At last,the length of the cam cables 150 a and 150 b that are wound from the camcable winding portion 210 to the cam module 220 until the let-off stateincreases, to thereby increase the draw length of the bowstring 140.

As shown in FIGS. 9 to 13, the cam cable guide member 300 according tothe second embodiment plays a role of guiding a portion of the camcables 150 a and 150 b extended from the rotating wheel 120 in parallelwith the pulley 110, and is rotatably coupled to the rotating shaft 101of the pulley 110 separately from the pulley 110 at one side surface ofthe rotating wheel 120, so as to be extended by a predetermined lengthin an arc-shaped form along the direction of extension of the cam cables150 a and 150 b. As shown in FIG. 13, two coupling units 301 areprotrudingly formed at one end of the cam cable guide member 300 inorder to couple the rotating shaft 101 to the cam cable guide member300, and through-holes through which the rotating shaft 101 of thepulley 110 is coupled are formed in the coupling units 301,respectively. Thus, the two coupling units 301 are coupled to therotating shaft 101 at both sides of one branch adjacent to the rotatingwheel 120 of the two branches forming the rear portion of each limb 103.In addition, the support member 310 that supports the cam cables 150 aand 150 b is formed at the other end of the cam cable guide member 300,in order to make a portion of the cam cables 150 a and 150 b that arewound on the rotating wheel 120 and then extended therefrom guided inparallel with the pulley 110. The reason why the cam cable guide member300 is made in an arch-shaped form is that since the cam cables 150 aand 150 b are bent to the other side surface of the pulley 110 in orderto be inserted into the cable guard 105 past the guide pulley 320, andthus the other end of the cam guide cable guide member 300 in which thesupport member 310 is formed, is subjected to receive a force in theopposite side of the pulley 110, the cam cable guide member 300 is madein an arch-shaped form to make the length of the cam cable guide member300 be long while making the distance from the rotating shaft 101 to thesupport member 310 be short, to thereby improve a counteraction forceagainst the force applied to the pulley 110 and prevent a deformity suchas bending of the cam cable guide member 300.

The support member 310 of the cam cable guide member 300 includes aguide pulley 320 and a support pulley 330 that are respectivelyrotatably coupled to two shaft members 302 and 303 respectively locatedat both sides of the cam cables 150 a and 150 b, in which the cam cables150 a and 150 b are supported between the guide pulley 320 and thesupport pulley 330. The guide pulley 320 plays a role of guiding the camcables 150 a and 150 b to be guided in parallel with the pulley 110, andis rotatably coupled to the shaft member 302 that is protruded towardthe pulley 110 at the other end of the cam cable guide member 300, inwhich a guide groove 311 for guiding the cam cables 150 a and 150 b isformed on the outer circumferential surface of the guide pulley 320. Theguide pulley 320 is formed closer to the rotating shaft 101 than thesupport pulley 330.

The support pulley 330 plays a role of guiding the cam cables 150 a and150 b to be guided in parallel with the pulley 110, together with theguide pulley 320, and simultaneously guiding the cam cables 150 a and150 b to be guided toward the cable guard 105 via the support pulley330. The support pulley 330 is formed farther from the rotating shaft101 at the front of the guide pulley 320 than the guide pulley 320, andis rotatably coupled to the shaft member 303 that is protruded towardthe pulley 110 at the other end of the cam cable guide member 300.

Since the cam cable guide member 300 is configured to have theabove-described structure, the cam cables 150 a and 150 b do not comeinto contact with the pulley 110 and the cam cables 150 a and 150 b arealso guided in parallel with the pulley 110 when the bowstring 140 ispulled. As a result, direction of a force applied to each of the camcables 150 a and 150 b is parallel to the bowstring 140, therebypreventing distortion of the bow limbs 103.

Here, a detailed description thereof will be omitted for otherconfigurations and operational effects of the second embodiment similarto those of the first embodiment.

As described above, the present invention has been described withrespect to particularly preferred embodiments. However, the presentinvention is not limited to the above embodiments, and it is possiblefor one who has an ordinary skill in the art to make variousmodifications and variations, without departing off the spirit of thepresent invention. Thus, the protective scope of the present inventionis not defined within the detailed description thereof but is defined bythe claims to be described later and the technical spirit of the presentinvention.

What is claimed is:
 1. A compound bow comprising: a bow main bodyincluding a handle at a central portion of which a grip portion isformed and a pair of limbs that are respectively coupled to both ends ofthe handle; upper and lower pulley assemblies each including a pulleythat is rotatably coupled to a rotating shaft formed on the rear end ofeach limb, and a cam that is coupled to one side of the pulley androtating with the pulley; a bowstring whose either end is wound andcoupled to the pulley of each of the upper and lower pulley assemblies;and two cam cables that are wound around the cam of each of the upperand lower pulley assemblies as the bowstring is pulled, in which one endof each of the two cam cables is coupled to one of the upper and lowerpulley assemblies, and the other end thereof is coupled to the other ofthe upper and lower pulley assemblies or the rotating shaft of the otherof the upper and lower pulley assemblies; wherein at least one of theupper and lower pulley assemblies further comprises: a rotating wheelthat is coupled with the rotating shaft of the pulley on the other sidesurface opposing to one side surface of the pulley to which the cam iscoupled, in which one of the two cam cables is coupled to the other sidesurface of the pulley, wound on the rotating wheel, and extended towardthe other of the upper and lower pulley assemblies; and a cam cableguide member one end of which is rotatably coupled to the rotating shaftof the pulley separately from the pulley, at one side of the rotatingwheel, in which the cam cable guide member is extended by apredetermined length along one of the cam cables extended toward theother of the upper and lower pulley assemblies from the rotating wheel,and at the other end of which a support member for supporting one of thecam cables is formed in order to make a portion of one of the cam cablesextended from the rotating wheel guided in parallel with the pulley. 2.The compound bow of claim 1, wherein the rotating wheel is rotatablycoupled to the rotating shaft separately from the pulley.
 3. Thecompound bow of claim 1, wherein the support member of the cam cableguide member comprises a guide pulley and a support pulley that arerespectively rotatably coupled to two shaft members respectively locatedat both sides of the cam cable, in which the cam cable is supportedbetween the guide pulley and the support pulley.
 4. The compound bow ofclaim 3, wherein a guide groove for guiding the cam cable is formed onan outer circumferential surface of the guide pulley.
 5. The compoundbow of claim 3, wherein the support pulley is formed at the front of theguide pulley, and is located at a longer distance from the rotatingshaft of the cam cable guide member than the guide pulley.
 6. Thecompound bow of claim 5, wherein the support pulley is formed to have anouter diameter of an outer circumferential surface of the support pulleythat guides the cam cable in contact with the cam cable becomes smallerinwards, and thereby guides the cam cable to a cable guard that iscoupled to the handle of the bow main body and pushes the cam cable inone direction.
 7. The compound bow of claim 3, further comprising asupport bar one end of which is rotatably coupled to the rotating shaftseparately from the pulley at the other side surface of the pulley towhich the cam cable guide member is coupled, so as to oppose the camcable guide member, and at the other end of which two supportprotrusions are formed for supporting each of the guide pulley and thepulley support of the cam cable guide member.
 8. The compound bow ofclaim 1, wherein two coupling portions to which the rotating shaft iscoupled are formed at one end of the cam cable guide member, in whichthe two coupling portions are coupled to the rotating shaft at bothsides of one of two branches adjacent to the rotating wheel of the twobranches that form a rear portion of the limbs.
 9. The compound bow ofclaim 8, wherein the cam cable guide member is made in an arch-shapedform.
 10. The compound bow of claim 8, wherein the support member of thecam cable guide member comprises a guide pulley and a support pulleythat are rotatably coupled to two shaft members located at both sides ofthe cam cable, in which the cam cable is supported between the guidepulley and the support pulley.